Biomechanical Modeling of Transcatheter Aortic Valve Replacement in a Stenotic Bicuspid Aortic Valve: Deployments and Paravalvular Leakage

Over 50% of the patients diagnosed with Calcific aortic valve disease (CAVD) have a Bicuspid Aortic Valve (BAV). In most clinical trials of Transcatheter aortic valve replacement (TAVR), BAV patients were excluded. Performing TAVR in calcified BAV patients may be associated with preprocedural complications due to the BAV asymmetrical structure. This study aims to develop refined computational finite element models aimed at simulating the deployments of Evolut R and PRO TAVR devices in calcified BAV. The paravalvular leakage (PVL) was also calculated by computational fluid dynamics (CFD) simulations in order to determine the influence of the inner cuff orientation and the efficiency of the Evolut PRO. Computed tomography scan of severely stenotic BAV patient was acquired. The 3D calcium deposits were generated and embedded inside a parametric model of the BAV. Deployments of the Evolut R and PRO inside the calcified BAV were simulated in five different bioprosthesis leaflets orientations. The hypothesis of asymmetric and elliptic stent deployment was confirmed. The fused cusp experienced a larger contact area with the stent and resulted in lower average pressure. Positioning the bioprosthesis commissures aligned with the native commissures was found to yield the lowest PVL. The Evolut PRO reduced the PVL in half compared with the Evolut R. The proposed biomechanical computational model could help assess the functionality of TAVR in BAVs.